Winding rod for reels of web material and a winding machine using said rod

ABSTRACT

The winding rod (A) comprises a longitudinal body ( 15 ) extending from a first end to a second end of the rod. It also comprises expandable elements ( 33 ) distributed around a longitudinal axis of the longitudinal body and at least one pressurization circuit for expanding said expandable elements. The expandable elements ( 33 ) are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, which also comprises an intermediate portion devoid of expandable elements.

TECHNICAL FIELD

The present invention relates to improvements to machines and systems for winding web material, particularly but not exclusively for the production of reels of paper, tissue paper, non-woven and similar articles of manufacture.

STATE OF THE ART

In many industrial fields it is necessary to wind a continuous web material to form reels intended for subsequent processing for the production of finished products aimed at consumers. In particular, in the paper manufacturing sector and in the production of non-woven fabrics and similar products, winding machines are used (so-called winders or rewinders) for the production of, reels or rolls of web material wound around tubular winding cores. These tubular winding cores are often mounted on a spindle or winding rod, the ends of which are normally engaged by gripping clamps or by pins, which the winding machine or rewinder is fitted with. Normally, the tubular winding cores are produced by cutting a tubular element and can come with different lengths, or axial dimensions. Normally, several tubular winding cores aligned with one another are mounted on a single winding rod. Onto each tubular winding core a respective continuous strip of web material is wound, which is obtained by longitudinally cutting a very wide continuous web material. In general, therefore, several reels of web material wound around respective tubular winding cores are simultaneously formed around each winding rod or spindle.

The winding rod inserted inside the tubular winding cores is usually provided, along its axial length, with expandable elements distributed around the longitudinal axis of the rod. The expandable elements are expanded pneumatically by means of a pressurization circuit, so that they press against the inner surfaces of the tubular winding cores in which the winding rod is inserted, to axially clamp the tubular winding cores onto the winding rod.

Winding machines or rewinders that use winding rods inserted inside tubular winding cores and axially clamped thereto are disclosed, for example, in EP0747308, EP1070675, EP1375401 and EP1375402.

Winding rods are subject to vibration during winding, especially at high rotation speeds and in the final phase of reel forming, because of the limited flexional stiffness of the winding rods, in particular due to the presence of housings for the expandable elements, which are needed to provide axial coupling between the winding rod and the tubular winding cores.

SUMMARY OF THE INVENTION

To achieve greater strength and flexional stiffness of the winding rod, the expandable elements of the winding rod are advantageously placed only in certain zones along the longitudinal extension of the winding rod. Preferably, the expandable elements are placed in the end portions, i.e. at the ends of the winding rod, while a mainly predominant portion of its longitudinal length does not have any expandable elements. In this manner, the predominant central portion of the winding rod can be made using an integral tubular element, i.e. without grooves, seats or cavities, for housing the expandable elements, thereby achieving a stiffer, stronger structure, as well as a substantial reduction in the weight of the winding rod.

According to an embodiment, the winding rod comprises in substance a longitudinal body extending from a first end to a second end, expandable elements distributed around a longitudinal axis of the longitudinal body, and at least one pressurization circuit for expanding said expandable elements. Advantageously, the expandable elements are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body. The longitudinal body comprises an intermediate portion without any expandable elements.

In advantageous embodiments, the pressurization circuit comprises a conduit extending from the first group of expandable elements to the second group of expandable elements and has at least one pressurization and de-pressurization valve, placed at one of the two ends of the longitudinal body. By means of the valve, the first group of expandable elements and the second group of expandable elements can be pressurized. In other embodiments, two pressurization and de-pressurization valves can be provided, one at each end of the winding rod. In this manner, the winding rod can be used without needing to be oriented with respect to the pressurization/de-pressurization system.

Advantageously, regardless of the number of pressurization and de-pressurization valves, the pressurization circuit may advantageously have a pneumatic connection between the first group of expandable elements and the second group of expandable elements, so that pressurization and de-pressurization of the winding rod can be achieved by means of a single operation and through a single valve.

In some embodiments, the expandable elements are in the form of laths extending parallel to the longitudinal body of the winding rod. For example, the winding rod may comprise housings for the first group of expandable elements and housings for the second group of expandable elements, said housings being in the form of longitudinal recesses distributed around the axis of the longitudinal body of the winding rod, and extending parallel to said longitudinal axis for a fraction of the overall length of the winding rod.

In some embodiments, the longitudinal body of the winding rod may comprise: a first shaft on which the first group of expandable elements is placed, and a second shaft on which the second group of expandable elements is placed; a tubular element arranged between the first shaft and the second shaft and torsionally and axially constrained to said first shaft and to said second shaft so as to form said longitudinal body.

In some embodiments, in order to achieve good mechanical properties and limited weight for the winding rod, the tubular element may be made of carbon fibers, for example by means of one or more helical windings of carbon fibers or filaments in a synthetic resin matrix.

In some embodiments, the winding rod may be fitted with a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid, these longitudinal passages being fluidly coupled with the first group of expandable elements and the second group of expandable elements, respectively. The pressurization fluid may be a gas or a gas mixture. Preferably the pressurization fluid may be air.

In some embodiments, the first longitudinal passage and the second longitudinal passage are connected by means of a conduit extending longitudinally inside an intermediate portion of the winding rod.

When the winding rod comprises a first shaft and a second shaft, the first longitudinal passage and the second longitudinal passage can be located in the first shaft and in the second shaft, respectively. Furthermore, the conduit connecting the two longitudinal passages may extend longitudinally inside the tubular element connecting the first shaft and the second shaft of the tubular element placed between the first shaft and the second shaft and preferably coaxial thereto.

At one or preferably at both ends of the winding rod bushings may be idly mounted on the shafts which form the end portions of the winding rod.

The invention also relates to a winding machine or rewinding machine comprising members for winding a web material, a feed path for the web material and at least one winding rod of the type described above. The winding members are preferably peripheral winding members. Furthermore, the possibility of using the winding rods described in central winding systems, or in combined (peripheral and central) winding systems, is not excluded. Those skilled in the art will know that the term peripheral winding, or surface winding, relates to a system of winding wherein the feed of the material to be wound and the rotation movement of the reel or roll being formed are achieved by means of members cooperating with the outer surface of the roll or reel, for example by means of winding rollers, winding belts and the like, or combinations thereof. Conversely, a central winding system is a system wherein the rotation movement is achieved through the winding rod around which the reel or roll is being formed.

Further possible features are described hereunder with reference to embodiments of the invention, and in the appended claims, which form an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by following the description and accompanying drawing, which shows a practical embodiment of the invention. More specifically, in the drawing:

FIG. 1 shows a schematic of a rewinding machine in which a winding rod according to the present disclosure can be used;

FIG. 2 shows a side view of a winding rod in a possible embodiment;

FIG. 3 shows a cross section according to in FIG. 2;

FIG. 4 shows an enlargement of detail IV in FIG. 3;

FIG. 5 shows an enlargement of the detail indicated by V in FIG. 3;

FIG. 6 shows an enlargement of the detail indicated by VI in FIG. 2;

FIGS. 7 and 8 show transversal cross sections along the lines VII-VII and VIII-VIII in FIG. 6;

FIG. 9 shows a longitudinal cross section of one end of a rod in another embodiment;

FIG. 10 shows a view according to X-X in FIG. 2.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The following detailed description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Additionally, the drawings are not necessarily drawn to scale. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.

Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase “in one embodiment” or “in an embodiment” or “in some embodiments” in various places throughout the specification is not necessarily referring to the same embodiment(s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

FIG. 1 schematically shows a rewinding machine with three rollers that can use the winding rod according to the invention. The rewinding machine, indicated as a whole by reference number 1, comprises an upper winding roller 3, which is movable in the direction shown by the double arrow f3 so as to move towards and away from a winding cradle formed by a second winding roller 5 and a third winding roller 7. FIG. 1 shows a reel or roll R during winding around a respective tubular winding core C, wherein a winding rod A in inserted. As noted above, generally several tubular winding cores C are inserted on the winding rod A, and therearound several reels or rolls R are formed in parallel or simultaneously.

The web material to be wound, shown at N, is fed around the third winding roller 7 and is wound around the roll or reel R due to the rotation movement imparted to the roll or reel R by the winding rollers 3, 5 and 7. The upper winding roller 3 is gradually raised in the direction of arrow f3 to move away from the winding cradle formed by the rollers 5, 7 as the diameter of the roll or reel R increases until winding has been completed.

The improvements that are the object of the present disclosure relate particularly to the configuration of the winding rod A, of which an exemplary embodiment is shown in FIGS. 2 to 5. Experts in the field will understand from reading the present description that the winding rod may also be used in winding machines or rewinding machines with a configuration different from the one schematically shown by way of example in FIG. 1. The winding rod described below can be used in all applications, wherein it is necessary to insert the winding rod inside one or more tubular winding cores and to axially block the winding rod to the tubular winding core(s) by means of expandable elements, which the winding rod is fitted with.

The winding rod A as a whole is shown in FIGS. 2 and 3, in a side view and in a longitudinal cross-section view, respectively. The winding rod A comprises a substantially cylindrical longitudinal body of length L. The ends of the winding rod may be fitted with bushings 11, 13 idly mounted by means of bearings onto the longitudinal body of the winding rod A, indicated as a whole by reference number 15.

The longitudinal body 15 of the winding rod A may comprise an intermediate portion 17, preferably with a hollow tubular shape, hereinafter referred to as tubular element 17. In some embodiments the tubular element 17 may be made of carbon fibers, for example by means of helical winding of continuous carbon filaments in a synthetic resin matrix.

In some embodiments the intermediate portion 17 and respective end portions 19, 21 of the longitudinal body 15 of the winding rod A may have substantially the same external diameter.

In FIG. 2 the length of the longitudinal body 15 is labeled L, while the total length of the winding rod A is labeled LA, and the length of the tubular element 17 is labeled L17. In some embodiments the length L17 may be more than half the overall length L of the longitudinal body 15 of the winding rod A and preferably more than half the overall length LA of the winding rod A. In some embodiments the length L17 may be equal to or greater than ⅔ and even more preferably equal to or greater than ¾ of the length L of the longitudinal body of the winding rod and the overall length LA of the winding rod.

In the embodiment shown, the tubular element 17 is torsionally and axially constrained at both ends to two respective end portions, hereinafter referred to as shafts 19 and 21. In some embodiments the shafts 19 and 21 may be fixed to the intermediate tubular element 17 by means of radial screws 23. In other embodiments, the coupling between the shafts 19, 21 and the intermediate tubular element 17 may be achieved in a different manner, for example by gluing. In the example shown (FIG. 2), coupling between the intermediate tubular element 17 and the shafts 19, 21 is made on a cylindrical interface surface. In other embodiments, particularly if the fixing is by means of gluing, conical mutual coupling surfaces may be provided.

As will become clearer below, the expandable elements, which the winding rod A is fitted with, are arranged solely on shafts 19 and 21, while the intermediate tubular element 17 does not have any expandable elements and therefore has a structure formed of a hollow cylindrical body with a circular cross-section, which is substantially integral, apart from the radial holes for screws 23, if present. The holes are placed only near the end zones of the intermediate tubular element 17 and all together take up a limited fraction of its length, for example less than a quarter, and preferably less than a sixth, of the length of the intermediate tubular element 17.

In some embodiments, the first shaft 19 is fitted with a first fluid passage 25. In some embodiments, the second shaft 21 is fitted with a second fluid passage 27, as well. The two fluid passages 25 and 27 may be connected to one another by means of a conduit 29 extending from one to the other of the shafts 19 and 21, extending longitudinally through the entire intermediate tubular element 17. The conduit 29 is preferably of a length greater than the intermediate tubular element 17 and is housed in the latter forming bends or a helix. In this way, assembly and disassembly of the individual components of the rod is simplified.

The two fluid passages 25 and 27 are fluidly coupled with expandable elements, wherewith the two shafts 19 and 21 respectively are fitted. The expandable elements provided on the shafts 19 and 21 may be substantially the same as one another. Here below a description is provided, of the configuration of the expandable elements that shaft 19 is fitted with, shown in detail in FIG. 4, it being understood that the expandable elements mounted on the shaft 21 may be substantially the same.

In some embodiments the expandable elements extend longitudinally parallel to the axis A-A of the winding rod A. In some embodiments the shaft 19 (and similarly shaft 21) has longitudinal housings, labeled 31, in which the respective expandable elements 33 are housed. In some embodiments a plurality of expandable elements 33 may be provided and distributed around the axis A-A of the winding rod A, with a preferably constant angular pitch. For example, six expandable elements 33 can be provided.

In some embodiments, as best shown in FIG. 4, each expandable element 33 comprises a longitudinal lath 35, housed in a respective housing 31. Each lath 35 is associated with an inflatable member, for example an air chamber 37, placed in the housing 31, between the bottom of the housing 31 and the respective lath 35. Each air chamber or inflatable member 37 is in fluid connection with the fluid passage 25, for example by means of at least one, preferably radial hole 39.

In some embodiments, each lath 35 is fixed to the inside of the housing 31, in the manner described in more detail below. With this arrangement, by pressurizing the fluid passage 25 in the manner described below, the fluid pressure in the inflatable member or air chamber 37 causes the radially outward flexional deformation of each lath 35 and therefore, if the winding rod A is inserted inside one or more tubular winding cores C, the mutual coupling between the winding rod A and the tubular winding cores C due to the effect of friction between the laths 35 and the inner surface of the tubular winding core. The laths 35 can also be fitted with spring elements 47 to ensure that the laths return to their rest position when the pressure inside the air chambers 37 is released.

As can be seen in particular in the sections shown in FIGS. 7 and 8, the laths 35 may have a transversal cross section in the form of an upturned T, or a dovetail, or another suitable shape, so as to be radially held inside the respective housings 31 which, like the laths 35, have a T-shape cross section or similar so as to form an undercut to prevent the radial escape of the laths 35.

In some embodiments, insertion of the laths 35 into the respective housings 31 is achieved by means of a widened portion of the housings 31, indicated by 31A (see in particular FIG. 6), and thanks to the flexibility of the laths 35. Once inserted into their respective housing 31, each lath 35 is axially held therein by means of a bracket 41 fixed with respective screws 41A to the corresponding shaft 17 or 19. At the end of each lath 35, opposite the end in contact with the bracket 41, a block 45 and a plate 46 are inserted into the respective housing 31. The block 45 has tightening members, for example grub screws 45A, by means of which the respective plate 46 is pushed radially inwards and pressed against the end of the air chamber 37 to create an air-tight seal. The opposite end of the air chamber is closed by compression by means of the respective bracket 41 and screw 41A. To that end, the bracket 41 has a tooth 41B pressing against the air chamber 37.

In some embodiments, at least one of the two ends of the winding rod A may be provided with a valve, schematically indicated by reference number 49 in FIG. 5, for pressurizing the pneumatic circuit contained in the winding rod and comprising the fluid passages 25, 27, the conduit 29, the radial holes 39 and the inflatable members or air chambers 37. By means of the valve 49, the entire pneumatic circuit can be pressurized, radially deforming outwards the laths 35 mounted on the shaft 19 and the corresponding laths, again labeled number 35 and shown schematically in FIG. 3, mounted on the second shaft 21.

As can be seen in FIG. 5, the valve 49 may be mounted at one end of the shaft 19 forming part of the longitudinal body 15 of the winding rod A. This end portion is surrounded by the first bushing 11 idly mounted by means of a bearing 51 on the shaft 19. Suitable seals 53 and 55 may protect the bearing 51, preventing dirt from getting in and/or lubricating grease from leaking out. In this manner the bushing 11 can rotate freely around the axis A-A of the winding rod A and can perform the normal functions assigned to these members even in known types of winding rods.

The opposite bushing 13 is mounted in the same way on the end formed by the shaft 21. This second end could be fitted with a second inflation or pressurization valve, similar to the valve 49, if the winding rod A is configured to be used independently of its orientation, i.e. when the winding rod is configured to be pressurized indifferently either from one end or the other. However, in the embodiment shown in FIGS. 2 and 3, the winding rod is an asymmetric type, with a single pressurization valve 49 at one end, corresponding to the bushing 11, while at the other end the fluid passage 27 made by the shaft 21 may be closed. Closure of the fluid passage 27 may be achieved by means of the same bushing 13.

In the example shown in the drawing, the bushing 13 is fitted with a gripping head 13A. In some embodiments, the gripping head 13A may be omitted. In other embodiments, also the bushing 11 may be fitted with a similar gripping or expansion head, not illustrated.

The configuration described above provides a winding rod A that is mainly formed of the intermediate tubular element 17, which may be made with a structure with high flexional stiffness, though very light, without notches or grooves at least in the central section thereof, thanks to the fact that the expandable elements 33 are all confined to the zone defined by the first shaft 19 and by the second shaft 21 or at the ends of the element 17.

The mainly preponderant part of the longitudinal body 15 of the winding rod A therefore has a much greater flexional stiffness than traditional winding rods, which have longitudinal recesses for housing the expandable elements extending all along their length. In this case, on the other hand, the length L17 of the intermediate tubular element 17 may even occupy more than ¾ of the overall length LA of the winding rod A, so that the latter has greater stiffness and a reduced tendency to vibrate when spinning rapidly to form rolls or reels R around the tubular winding cores C placed on the winding rod A and axially blocked thereon.

FIGS. 9 and 10 show another embodiment, limited to an end portion of the rod. Identical or corresponding parts are indicated with the same reference numbers.

In this exemplary embodiment, the two shafts 19, 21 (of which only shaft 19 is shown in the drawing) are of very limited length and simply form a sort of connection element between the respective bushings 11, 13 and a central tubular element, here labeled 117. The central tubular element 117 may be made substantially in the same way as the tubular element 17, for example with carbon fiber. However, unlike the previously described embodiment, in FIGS. 9 and 10 the expandable elements (again labeled 33) are placed in slots 34 made in the tubular wall of the central tubular element 117. In some embodiments the expandable elements 33 are mounted on plates or other supports 36, interposed between the inner surface of the central tubular element 117 and an air chamber 137, which may be single and common for all the expandable elements 33 at each end of the the rod A.

Each air chamber 137 may be inflated by means of a valve 49 and a conduit or fluid passage 25, fitted on each end of the rod A. In some embodiments, the two air chambers 137 placed at the two ends of the rod A may be connected by a conduit 29, in a manner similar to that described with reference to FIGS. 1 to 8. In this manner, inflation can be achieved indifferently from either of the two ends of the rod A, if there are valves 49 at both ends, or from one end only, if the other end has no valve.

The embodiments described above and illustrated in the drawings have been discussed in detail as examples of embodiment of the invention. Those skilled in the art will understand that many modifications, variants, additions and omissions are possible, without departing from the principles, concepts and teachings of the present invention as defined in the appended claims. Therefore, the scope of the invention must be determined purely on the basis of the broadest interpretation of the appended claims, comprising these modifications, variants, additions and omissions therein. The term “comprise” and derivatives thereof do not exclude the presence of further elements or steps besides those specifically indicated in a given claim. The term “a” or “an” preceding an element, means or characteristic of a claim does not exclude the presence of a plurality of these elements, means or characteristics. When a device claim lists a plurality of “means”, some or all of these “means” can be implemented by a single component, member or structure. The stating of given elements, features or means in distinct dependent claims does not exclude the possibility of said elements, features or means being combined with one another. When a method claim lists a sequence of steps, the sequence in which these steps are listed is not binding, and can be modified, if the particular sequence is not indicated as binding. Any reference numbers in the appended claims are provided to facilitate reading of the claims with reference to the description and to the drawing, and do not limit the scope of protection represented by the claims. 

1. A winding rod for winding reels of web material, the winding rod comprising: a longitudinal body extending from a first end to a second end, expandable elements distributed around a longitudinal axis of the longitudinal body; at least one pressurization circuit for expanding said expandable elements, wherein the expandable elements are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, said longitudinal body comprising an intermediate portion devoid of expandable elements, the longitudinal body of the winding rod comprising a first shaft and a second shaft and a tubular element placed between the first shaft and the second shaft and torsionally and axially constrained to said first shaft and said second shaft, so as to form said longitudinal body, the first shaft and the second shaft being fitted respectively with a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid, said first longitudinal passage and said second longitudinal passage being fluidly coupled to the first group of expandable elements and the second group of expandable elements, respectively.
 2. A winding rod according to claim 1, wherein the intermediate portion has a cylindrical outer surface with a diameter substantially corresponding to a diameter of the end portions in which the expandable elements are located.
 3. A winding rod according to claim 1, wherein said at least one pressurization circuit comprises a fluid connection from the first group of expandable elements to the second group of expandable elements and said at least one pressurization circuit has at least one pressurization and de-pressurization valve, placed at one of said first end or second end of the longitudinal body, by means of which both the first group of expandable elements and the second group of expandable elements can be pressurized.
 4. A winding rod according to claim 1, wherein said expandable elements are in a form of laths extending parallel to the longitudinal body of the winding rod.
 5. A winding rod according to claim 1, further comprising housings for the first group of expandable elements and housings for the second group of expandable elements.
 6. A winding rod according to claim 5, wherein said housings are in a form of longitudinal recesses distributed around the longitudinal axis of the longitudinal body of the winding rod, and extending parallel to said longitudinal axis.
 7. A winding rod according to claim 6, wherein each of said longitudinal recesses contains an air chamber, wherein inflation of said air chamber causes a radial expansion of the expandable elements. 8-9. (canceled)
 10. A winding rod according to claim 1, wherein the first longitudinal passage and the second longitudinal passage are flow connected to one another by means of an intermediate conduit extending longitudinally inside an intermediate portion of the winding rod.
 11. A winding rod according to claim 1, wherein said tubular element is made of carbon fibers.
 12. A winding rod according to claim 1, wherein the first longitudinal passage and the second longitudinal passage are fluidly coupled by means of a conduit extending longitudinally inside the tubular element placed between the first shaft and the second shaft.
 13. A winding rod according to claim 1, wherein the first group of expandable elements is mounted on the first shaft and the second group of expandable elements is mounted on the second shaft.
 14. A winding rod according to claim 1, wherein the first group of expandable elements and the second group of expandable elements are mounted at respective ends of the tubular element.
 15. A winding rod according to claim 12, further comprising a single air chamber for each group of expandable elements, wherein inflation of said single chamber causes a radial expansion of respective expandable elements.
 16. A winding rod according to claim 1, wherein the intermediate portion devoid of expandable elements extends for at least two-thirds of the overall length of the winding rod, and preferably for at least three-quarters of said overall length.
 17. A winding rod for winding reels of web material, the winding rod comprising: a longitudinal body extending from a first end to a second end, expandable elements distributed around a longitudinal axis of the longitudinal body; at least one pressurization circuit for expanding said expandable elements, the expandable elements being distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, said longitudinal body comprising an intermediate portion devoid of expandable elements, the intermediate portion having a cylindrical outer surface with a diameter substantially corresponding to a diameter of the end portions in which the expandable elements are located, a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid being provided, said first longitudinal passage and said second longitudinal passage being fluidly coupled to the first group of expandable elements and the second group of expandable elements respectively, the first longitudinal passage and the second longitudinal passage being flow connected to one another by means of an intermediate conduit extending longitudinally inside said intermediate portion of the winding rod.
 18. A winding machine or re-winding machine comprising members for winding a web material, a feed path for the web material and at least one winding rod, said at least one winding rod comprising a longitudinal body extending from a first end to a second end, expandable elements distributed around a longitudinal axis of the longitudinal body and at least one pressurization circuit for expanding said expandable elements, wherein the expandable elements are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, said longitudinal body comprising an intermediate portion devoid of expandable elements, the longitudinal body of the winding rod comprising a first shaft and a second shaft and a tubular element placed between the first shaft and the second shaft and torsionally and axially constrained to said first shaft and said second shaft, so as to form said longitudinal body, the first shaft and the second shaft being fitted respectively with a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid, said first longitudinal passage and said second longitudinal passage being fluidly coupled to the first group of expandable elements and the second group of expandable elements, respectively.
 19. A machine according to claim 18, wherein the winding rod is a peripheral winding means.
 20. A winding rod according to claim 2, wherein said at least one pressurization circuit comprises a fluid connection from the first group of expandable elements to the second group of expandable elements and said at least one pressurization circuit has at least one pressurization and de-pressurization valve, placed at one of said first end or second end of the longitudinal body, by means of which both the first group of expandable elements and the second group of expandable elements can be pressurized.
 21. A winding rod according to claim 2, wherein said expandable elements are in a form of laths extending parallel to the longitudinal body of the winding rod.
 22. A winding rod according to claim 3, wherein said expandable elements are in a form of laths extending parallel to the longitudinal body of the winding rod.
 23. A winding rod according to claim 2, further comprising housings for the first group of expandable elements and housings for the second group of expandable elements.
 24. A winding rod according to claim 23, wherein said housings are in a form of longitudinal recesses distributed around the longitudinal axis of the longitudinal body of the winding rod, and extending parallel to said longitudinal axis.
 25. A winding rod according to claim 24, wherein each of said longitudinal recesses has an axial length that is less than half an axial length of the rod, and each of said longitudinal recesses is divided into two groups of longitudinal recesses, a first of said two groups of longitudinal recesses extending from one of said first end and second end and another one of said two groups of longitudinal recesses extending from another one of said first end and second end, a central portion of the winding rod being devoid of said longitudinal recesses. 